Design Of Miniaturized MIMO Antenna With Low Mutual Coupling

With the rapid development of wireless communication today, the communication technology has successfully entered the era of 4G communications. Since people want to get more and more rapid and high-quality service, higher requirements of performance and size of the mobile terminal antennas are proposed. As necessary technology in the development of wireless communication, MIMO technology owns the unique advantage in improving the system channel capacity and data transfer rate. However, with the demand of mobile terminal miniaturization, how to reduce the mutual coupling between the antenna elements in a limited space becomes a core issue. In this dissertation, focus on the decoupling problem of mobile-terminal MIMO antenna, we study antenna decoupling techniques by changing the structure of antenna and designing decoupling network. The contents are shown as follows:1. A metamaterial structure loaded MIMO antenna. By altering the geometry and dimensions of the metamaterial cell, it can absorb electromagnetic waves of different frequency bands. Based on the study of metamaterial structure, this technique is extended to the design of a compact MIMO antenna with high isolation. The MIMO antenna has an operating bandwidth of 5.8 GHz WLAN band.2. A stub-loaded MIMO antenna with dual band. It is studied that stub-loaded radiator can effectively change the current distribution, and reduce the coupling current between the antenna port, thereby enhancing the port isolation of the antenna. In order to explain the mechanism well, a stub-loaded dual-element MIMO antenna with dual band is also presented in the thesis. The MIMO antenna has an operating bandwidth of entire WLAN band.3. A rational distribution based multi-element MIMO anetenna.in UWB application. In this thesis, We design a UWB MIMO antenna with the rational distribution of antenna elements. This MIMO antenna achieve low mutual coupling without using any other decoupling methods, since their antenna elements location and angular orientation are reasonable in a small area. It has an advantage over other decoupling methods which need complex decoupling structure. The MIMO antenna gets a high isolation in the UWB operating band, which means the 3.1GHz-10.6GHz.4. Both the summary and conclusions of the researches in this thesis are presented. And the expectation for the future study is shown.